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Chevy Truck Pure Performance Solid Axle Swap - Something SolidPure Performance Solid-Axle Chevy From the December, 2008 issue of 4Wheel & Off-Road By Fred Williams Photography by Fred Williams
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We've been asked many times how to put really big tires under late-model GM trucks, but we've always been adamant that the front suspension isn't designed for giant rubber. You've heard our gripes about independent front suspension (IFS) before; we're not big fans because it breaks when you start adding big torque, big tires, and extreme terrain. The upgrades for IFS are getting better, but most suspension companies don't increase the strength of the front axle when they incorporate the lift on these late-model trucks. Until now. Pure Performance (the parent company of Rock Krawler Suspension) has been making suspensions for late-model Chevy trucks for a while, but when the company started looking into a lift for the 3/4- and 1-ton trucks it decided that a solid-axle swap kit was the only way to get enough strength to get the power from the Duramax engine to the ground without breaking parts. This new solid-axle-swap suspension kit replaces all the independent parts with an AAM axle from an '03-or-newer Dodge 3/4- or 1-ton truck. The Dodge axle was chosen because the front driveshaft is on the driver side, the same as the Chevrolet, and more importantly the speed sensor from the Chevy is interchangable with the Dodge one so that all the speedometer, transmission, and engine control systems still work without issue. To keep ride quality as close to stock as possible, the Pure Performance kit uses coilover front shocks and a four-link with track-bar design. The kit is engineered to give 8 to 10 inches of lift and clear 37x13.5R17 tires, though using taller coilovers and shocks can result in closer to 13 inches of lift.  1. We recently visited NorCal...  1. We recently visited NorCal Truck in Livermore, California, to document the installation of the Pure Performance solid-axle swap kit on an '08 GMC 2500HD. The first step is to get the truck up on a lift and remove all the IFS parts. Starting with a new truck like we did is a pleasure because everything is dirt- and rust-free. If you're considering adding this kit to your used truck, we suggest having the chassis steamcleaned. It often costs around $100 or so for a professional hot steamclean, but it's worth the money.  2. In addition to removing...  2. In addition to removing all the bolt-on front suspension components, some brackets will need to be cut off the frame as well, making the swap nonreversible (though we can't imagine wanting to go back to IFS after the work of swapping in a straight axle). Other brackets are left on the chassis and used to align new shock hangers. After the unneeded metal is cut off, the hydroformed chassis is ground smooth for a clean finish.  3. While the truck was being...  3. While the truck was being prepped, NorCal was also working on the new front axle. These AAM axles came from '03-and-newer Dodge 3/4- or 1-ton trucks. Most of the axle brackets will be cut off (front), but not before they are used to align the new Pure Performance link brackets (rear). The swap kit can also be used with a driver-side Dana 60 front axle, but the AAM axle has the same speed sensor and uses the same size U-joints as the 60. Although the AAM axles are only 33-spline, they are often found under the Cummins-powered 1-tons, and we feel they're comparable in strength to a Dana 60. Current market price on a used front AAM axle is between $1,000 and $2,500, similar to a complete 60.  4. The new brackets as well...  4. The new brackets as well as the entire kit will require some good welding skills, but most of the bracket alignment is based off of old brackets on either the axle or frame to make assembly quick and nearly idiot-proof. The NorCal crew burned all the brackets in with a Miller 251 MIG welder after sufficiently cleaning the axle and frame of old paint and rust.  5. Just behind the engine...  5. Just behind the engine on the chassis of the truck there is a seam where the two sections of frame are welded together at the factory. This is where the front suspension links will be mounted to the chassis. The link mount brackets are located across the seam to additionally tie into both frame sections.  6. The new brackets also use...  6. The new brackets also use small gussets to help support any lateral loads that might be applied to the links. All the gussets and brackets are 3/16-inch laser-cut steel.  7. The front upper A-arm mounts...  7. The front upper A-arm mounts are reused to align the shock mounts. Below that is the new track-bar frame bracket. Our one complaint with the design is that we feel the track-bar bracket should tie into a larger portion of the frame. We're sure the kit will be fine, but a larger bracket could add strength for those looking to seriously abuse their new fullsize.  8. The Pure Performance links...  8. The Pure Performance links are made from solid-steel 2-inch bar and have a large bushing at the frame and a rebuildable spherical joint at the axle end.  9. This particular customer...  9. This particular customer chose to run taller King coilover shocks, resulting in close to 12 1/2 inches of lift to clear 38-inch tires. The standard kit comes with coilovers that give 8 to 10 inches of lift with an even 4 or 5 inches of up and down travel, making for a well-rounded suspension.  10. This is one of the coolest...  10. This is one of the coolest parts of this suspension. In the past, any solid-axle late-model Chevy conversion either required a custom axle with custom speed sensors or had a dash full of warning lights when the computer failed to find the correct speed sensor. By using the Dodge AAM front axle, the GM tone ring indicator plugs right into the axle and the truck doesn't even realize it's been upgraded from a wobbly front end to a solid straight axle.  11. To complement the new...  11. To complement the new front suspension, Pure Performance offers a proprietary set of Deaver rear leaf springs tuned to spec and offering a level 8 inches of lift in the rear. Additional rear lift blocks are also available if a taller truck is desired. Again, King remote-reservoir shocks were used to control the rear axle.  12. The last two views help...  12. The last two views help show how the front-suspension track bar and steering all follow identical angles to fight bumpsteer. The four-link design with track bar is a great all-around design and, with the addition of a front sway bar, results in a big stable truck excellent for daily driving and off-roading.
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